Implement NonElementParentNode for DocumentFragment

2 files changed, 14 insertions, 0 deletions

diff --git a/components/script/dom/documentfragment.rs b/components/script/dom/documentfragment.rs
index 2f0ccecda5c..3eac9df6bac 100644
--- a/components/script/dom/documentfragment.rs
+++ b/components/script/dom/documentfragment.rs
@@ -17,6 +17,7 @@ use dom::eventtarget::{EventTarget, EventTargetTypeId};
 use dom::htmlcollection::HTMLCollection;
 use dom::node::{Node, NodeTypeId, window_from_node};
 use dom::nodelist::NodeList;
+use string_cache::Atom;
 use util::str::DOMString;
 
 // https://dom.spec.whatwg.org/#documentfragment
@@ -58,6 +59,18 @@ impl DocumentFragmentMethods for DocumentFragment {
         HTMLCollection::children(window.r(), NodeCast::from_ref(self))
     }
 
+    // https://dom.spec.whatwg.org/#dom-nonelementparentnode-getelementbyid
+    fn GetElementById(&self, id: DOMString) -> Option<Root<Element>> {
+        let node = NodeCast::from_ref(self);
+        let id = Atom::from_slice(&id);
+        node.traverse_preorder().filter_map(ElementCast::to_root).find(|descendant| {
+            match descendant.get_attribute(&ns!(""), &atom!(id)) {
+                None => false,
+                Some(attr) => *attr.value().as_atom() == id,
+            }
+        })
+    }
+
     // https://dom.spec.whatwg.org/#dom-parentnode-firstelementchild
     fn GetFirstElementChild(&self) -> Option<Root<Element>> {
         NodeCast::from_ref(self).child_elements().next()
diff --git a/components/script/dom/webidls/DocumentFragment.webidl b/components/script/dom/webidls/DocumentFragment.webidl
index 7dfbcc573df..eb2b7d6696d 100644
--- a/components/script/dom/webidls/DocumentFragment.webidl
+++ b/components/script/dom/webidls/DocumentFragment.webidl
@@ -8,4 +8,5 @@
 interface DocumentFragment : Node {
 };
 
+DocumentFragment implements NonElementParentNode;
 DocumentFragment implements ParentNode;